As the critical dimension of metal oxide semiconductor field effect transistor (MOSFET) devices continues to shrink, the short channel effect becomes more problematic. Fin field effect transistor (FinFET) devices have good control capability of gates to effectively suppress the short channel effect. FinFET devices can also reduce random dopant fluctuation to improve the stability of the devices. Thus, FinFET devices are widely used in the design of small-sized semiconductor elements.
Laterally Diffused Metal Oxide Semiconductor (LDMOS) devices are one of the important components for developing cost-effective system-on-a-chip applications.
The present inventors discovered that, in a conventional LDMOS device, a portion of a gate oxide and a portion of a metal gate are disposed on a shallow trench isolation (STI) region, the portion of the gate oxide on the STI region is also disposed between the metal gate and a drift region. In operation, the voltage difference between the metal gate and the drift region would tend to cause breakdown (puncture) to the gate oxide, thereby limiting the source and drain breakdown performance of an LDMOS device.
Therefore, there is a need for improved LDMOS device structures and methods for manufacturing such semiconductor devices to overcome these drawbacks.